Air and Moisture Tightness

On the exterior side of a building, a wind barrier acts as a shield against the forced convection that allows cold air from the ventilation gap into the building fabric. Local building regulations provide requirements for the air permeability of wind barriers.

On the interior side of a building, a vapour barrier stops moist indoor air from penetrating the structure from the inside.

To achieve good overall air tightness in a building, seal and safeguard all joints, corners, walls adjoining ceilings and foundations, air barriers between window and door sills, penetrations for pipes, electrical installations, ducts and chimneys.

Modern building envelopes are complex. They require that you consider insulation continuity and air tightness early in the design process. When planning and implementing how to tighten a building, remember the following basic principles:

Simplify the form where possible. Minimize the number of joints and connections.

Define the line of the air barrier as early as possible. Protect the air barrier during construction.

Decide and specify which materials will form the air barrier.

Make the vapour barrier seams with a 100–200 mm overlap.

Use tape or butyl for tightening connections or around installations.

Where the barrier has to be squeezed use a flexible air tightening, such as PAROC XSS 001.

If holes appear in the vapour barrier during installation, tape them with PAROC XST 012. In some cases, replace the whole barrier.

Application:

PAROC solution:

Vapour / Air barrier layer

The vapour barrier needs to be age-resistant and accurately fit the area where it’s used. Paroc supplies three different versions of PE foil for this purpose.
• PAROC XMV 020
• PAROC XMV 012
• PAROC XMV 012zcf

Seams of vapour barriers

Holes in the vapour/air barrier

The vapour barrier has to be unbroken. For minor damage that occurs during installation, fix with
• PAROC XST 012

Vapour barrier connection between window and walls

The point where the vapour barrier meets windows is absolutely critical. Every building presents new circumstances, so there are several ways to solve this challenge. Paroc recommends PAROC Corner tight. Because you can turn Corner tight to fit different sizes of window recesses, it is a flexible, easy-to-install solution. Once in place, simply tape the seal to the barrier.

• PAROC Corner tight
• PAROC XST 100 FlexWrap NF.

Sealing of door / window frames

Joints between parts of the structure often run the full width of the wall, making them crucial for the overall tightness of the building. Joints demand special attention during installation, and there are a variety of ways to tighten them.

Capillary breaks for foundations

Sealing penetrating ventilation pipes

Pipes or other shaped forms which penetrate the building envelope are challenging to get air-tight. Use PAROC XST 100 FlexWrap NF to tighten even the most complicated installations. You can also tape a collar to the air and moisture barrier.

• PAROC XST 100

Corners

The vapour barrier has to be continuous in room corners where two walls meeting the ceiling. Form-shaped corner tightening products help you reach the optimal solution.
• PAROC XMV 003

As a pioneer in the insulation industry Paroc aims to fulfil the changing demands today’s world sets for the environments we build for ourselves. Sustainable and durable choices can ensure fire safe, energy-efficient and comfortable living and working environments in the future. Our reliable solutions and unique ability to innovate encourage others to follow us. By staying ahead of the competition and achieving growth, we can ensure the development of our solutions, operations, and employees. We are open in our operations as we think that by inspiring others we can shape the entire construction industry.